Huge performance difference when building ISO image on RH vs Debian

I have this strange problem that's happening on CentOS 9 and Fedora 35. I'm trying to build alpine ISO using tools inside docker image (guide based on https://wiki.alpinelinux.org/wiki/How_to_make_a_custom_ISO_image_with_mkimage). And when building the ISO (which consists of building kernel, squashfs and putting it all together in an ISO file) it takes 20-22 minutes for 160MB ISO file.

Now here comes the huge performance difference:

• Fedora 35 is on linux laptop with an i5-6300HQ, 16GB RAM, running 5.17.12-200 kernel and Docker version 20.10.17
• CentOS 9 is running on a VM located on a host with i7-4790k with 32GB of RAM in a VMWare Workstation. CentOS 9 has 4vCPUs assigned and 8G of RAM, has a kernel version 5.14.0 and Docker version 20.10.18

Both of those environments take same amount of time to build the ISO. I've cloned CentOS 9 VM and installed Debian Bullseye (on same host as CentOS 9). So literally same hardware setup as CentOS 9 , however Debian is running Kernel 5.10 and same Docker version - 20.10.18. On Debian, same docker image, same source - it takes only 5-6 minutes to complete! That is huge difference!

At the moment i thought that it might be due to some weird kernel problem, so i changed repo on debian to use bullseye-backports and installed 5.14.0. And build time still takes 5-6 minutes on Debian and 20-22 minutes on CentOS9.

Not really sure why is that much difference and i would like some help to figure it out.

Below is Dockerfile I've used to put together build environment

FROM alpine:3.16.2

COPY chroot/entrypoint.sh /

RUN \
    apk add ifupdown-ng=0.12.1-r0 openrc=0.44.10-r7 \
        alpine-conf fakeroot=1.25.3-r3 \
        openssl libattr=2.5.1-r1 \
        attr=2.5.1-r1 libacl=2.3.1-r0 \
        tar=1.34-r0 pkgconf \
        patch=2.7.6-r7 libgcc=11.2.1_git20220219-r2 \
        libstdc++=11.2.1_git20220219-r2 lzip=1.23-r0 \
        ca-certificates brotli-libs=1.0.9-r6 \
        nghttp2-libs=1.47.0-r0 libcurl \
        curl abuild=3.9.0-r0 \
        binutils libmagic=5.41-r0 \
        file=5.41-r0 libgomp=11.2.1_git20220219-r2 \
        libatomic=11.2.1_git20220219-r2 gmp=6.2.1-r2 \
        isl22=0.22-r0 mpfr4=4.1.0-r0 \
        mpc1=1.2.1-r0 gcc=11.2.1_git20220219-r2 \
        musl-dev=1.2.3-r0 libc-dev=0.7.2-r3 \
        g++=11.2.1_git20220219-r2 make=4.3-r0 \
        fortify-headers=1.1-r1 build-base=0.5-r3 \
        expat=2.4.8-r0 pcre2=10.40-r0 \
        git alpine-sdk=1.0-r1 \
        ncurses-terminfo-base=6.3_p20220521-r0 ncurses-libs=6.3_p20220521-r0 \
        readline=8.1.2-r0 bash=5.1.16-r2 \
        dosfstools=4.2-r1 lddtree=1.26-r2 \
        xz-libs=5.2.5-r1 zstd-libs=1.5.2-r1 \
        kmod=29-r2 kmod-openrc=29-r2 \
        libblkid=2.38-r1 argon2-libs=20190702-r1 \
        device-mapper-libs=2.02.187-r2 json-c=0.16-r0 \
        libuuid=2.38-r1 cryptsetup-libs=2.4.3-r0 \
        kmod-libs=29-r2 mkinitfs \
        grub=2.06-r2 grub-efi=2.06-r2 \
        mtools=4.0.39-r0 lz4-libs=1.9.3-r1 \
        lzo=2.10-r3 squashfs-tools=4.5.1-r0 \
        sudo=1.9.10-r0 blkid=2.38-r1 \
        syslinux=6.04_pre1-r10 libburn=1.5.4-r1 \
        libedit=20210910.3.1-r0 libisofs=1.5.4-r2 \
        libisoburn=1.5.4-r2 xorriso=1.5.4-r2 && \
    adduser build \
        -G abuild \
        -D -s /bin/bash \
        -h /build && \
    echo "%abuild ALL=(ALL) NOPASSWD:ALL" > /etc/sudoers.d/abuild && \
    su build -c "abuild-keygen -a -i -n" && \
    mv /build/.abuild /

VOLUME build
USER build
ENV USER=build

ENTRYPOINT [ "/entrypoint.sh" ]
CMD [ "/build/aports/scripts/start.sh" ]

Build can be triggered by running following command inside docker container. Scripts above are just adjusted for additional environment check.

/build/aports/scripts/mkimage.sh --tag test --outdir ~/iso --arch x86_64 --repository http://dl-cdn.alpinelinux.org/alpine/v3.16/main --repository http://dl-cdn.alpinelinux.org/alpine/v3.16/community --profile base

And once again - comparison table

Specs of Physical red-hat based os (Fedora 35) running on a laptop and same issue